Product Description:

The 132H8446 soft starter is built by Danfoss within the MCD Soft Starters series. As a solid-state motor starter, it gradually raises supply voltage to the motor windings, lowering starting current and mechanical wear on pumps, fans, and material-handling drives in automated plants. After the ramp-up cycle, its integrated bypass transfers the running load to contactors, reducing thermal stress on the thyristors and improving overall efficiency.

Rated for mains systems up to 480 V AC, the unit handles a continuous motor current of 361 A, making it suitable for medium-sized induction machines delivering as much as 300 HP. Control electronics are energized by a separate 120 VAC supply that keeps logic and pilot relays isolated from the power circuit. During acceleration, the power section is gated through an internal bypass contactor; once full speed is reached, this contactor closes, diverting load current away from the SCRs to limit heat dissipation. The device is intended for installations fed with three-phase power, allowing symmetrical torque development and balanced phase currents across the connected motor. At this voltage level, the starter’s silicon devices maintain adequate dv/dt margins, ensuring reliable firing even under lightly regulated feeder conditions.

Housed in an enclosed chassis that meets the sealing requirements of a NEMA 12 installation, the starter blocks airborne dust and oil drips commonly present near machining centers. The heavy-gauge cabinet also provides finger-safe access to the line and load terminals. Its thermal and semiconductor sizing earns a heavy-duty rating, allowing the VLT Soft Starter MCD product group to perform six starts per hour with 350% current for 30 seconds without derating. Panel builders can wire the bypass, control, and ground lugs directly inside the enclosure, minimizing external hardware and reducing panel depth.